Telephone



' 4 SheetsSheet 1. S. D. FIELD.

(No Model.)

TELEPHONE.

No. 433,120. Patented July 29, 1890.

W Z Z/ I/VVENTOR WITNESSES (No Model.) 4 Sheets-Sheet 2.

S. D. FIELD.

TELEPHONE.

No. 433,120. Patented July 29,1890.

(9 QAQA a E '8 5 M F.

WITNESSES INVENTFCFI;

4 Sheets-Sheet 3. S. D. FIELD.

(No Model.)

TELEPHONE.

Patented Jfily 29, 1890.

WITNESSES W a/w'd (i [mi IN ENTOR (No Model.) 4 Sheets-Sheet 4.

S.'D. FIELD.

TELEPHONE. 7 No. 433,120. Patented July 29,1890.

. i fi v; s U H m N v k WITNESSES INVENTOR My UNITED STATES PATENTOFFICE.

STEPHEN DUDLEY FIELD, OF YONKERS, NEIV YORK.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 433,120, dated July 29,1890.

Application filed June 21,1887. Serial No. 2&2,00l- (No model.)

To aZZ whom it may concern.-

Be itknown that I, STEPHEN DUDLEYFIELD, a citizen of the United States,residing in Yonkers, in the county of Vestchester and State of New York,have invented certain new and useful Improvements inTelephone-Transmitters; and I do hereby declare that the following is afull, clear, and exact description of my invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention consists in constructing an apparatus which automaticallymakes and breaks an electric circuit with a rapidity too great for itseffects to be appreciated by the ear, and in so combining the apparatuswith a diaphragm that sound waves projected against the same are causedto bridge over more or less of said makes and breaks of the circuit inproportion to the rapidity with which the sound-waves succeed eachother.

My invention maybe embodied in a variety of constructions, several ofwhich are illustrated in the drawings accompanying this specification,in which Figures 1, 2, 3, and l represent, diagrammatically, fourdifferent embodiments of my invention.

In Fig. 1 I show two diaphragms D and M, supporting, respectively, twoplatinum contact-points E and G. One of the diaphragms is supportedabove the other, and is maintained in a state of tension by means of afine wire 0 of considerable electrical resistance. The drawings show,besides the parts above described, the usual battery B, an inductioncoilII, together with a switch A and the elec trical circuits. They alsoshow an adj ustingscrew 0 for regulating the tension of the upperdiaphragm through the wire 0. It will be seen that the circuit ofbattery B passes normally through the insulated metallic frame J of thetelephone and the wire 0 to the dia phragm D. It will also be observedthat there is a short circuit by way of wire I between the contact-pointGand the frame J. The tension of the wire C is normally sufficient toseparate'the points E and Gr. Vhen, however, the switch A is closed andthe current from battery B passes over wire 0, the latter will be causedto elongate and will allow said points to come into contact. The currentwill thus be shunted around the wire 0 through a path of approximatelyno resistance, and as a result the fine wire, becoming co0l,willcontract and separate the contact-points. The apparatus thus becomes acircuit-breaker, working with almost inconceivable rapidity so long asthe current from battery B continues to circulate. The makes and breaksare so rapid as to pass beyond the limit of receptivity of the car. Nowit is evident that sound-waves striking upon the diaphragm F will alterthe relative positions of the points E and G, tending to prolong theirrespective contacts. These prolonged contacts will produce effects whichare audible, and if they follow each other in the proper sequencearticulate speech may be transmitted and reproduced in suitable attachedreceiving instruments. In short, the drawings, Fig. 1, represent anapparatus constructed to send vibrations or pulsations over an electriccircuit at a rate too great for recognition by the sense of hearing,such apparatus being combined with means for prolonging at will thevibrations or pulsations by bridging over several of them into one. Themeans for prolonging the vibrations are attached, in this instance, to adiaphragm which is capable of being acted upon by the voice, so as tocause the prolongations to take place in proper sequence for reproducingarticulate speech. This is the principle which underlies theconstruction illustrated in all the drawings.

In Fig. 2 the points E and G are supported, respectively, upon levers Sand F, the former being pivoted at 7L and the latter at (Z. Therelations of the two levers can be adjusted by means of the screws \Vand X,the former of which bears against the lever S at one end and thelatter against the rubber spring K, which is located between the otherend of the lever and the screw \V. The circuit of battery l) in thisapparatus, when the key A is closed, passes, by way of wire 1, key A,wire 2, adj usting-screw O, and fine wire G, to the lever S, and back to.the battery by way of the screw X and the wire 3. The closing of thekey will therefore cause the current of battery 13 to pass through thewire 0, thus heating and causing it to expand. The wire will accordinglybe lengthened and the tension upon the lever S will be relaxed, allowingit to move toward the lever F by reason of the pressure exercised uponit by the rub- ICC contact between the points E and G, whereupon theabove operation will be repeated automatically as long as the key A iskept closed.

The lever F is connected by a link N with a diaphragm M, so that it willpartake of all the movements of the said diaphragm. The said lever beingcentrally pivoted, it is obvious that its outer end will have a reversemotion to that given the .inner end by the diaphragm. A sound-wavestriking upon the diaphragm M will therefore tend to cause a separationof the contacts E G and to prolong the expansion of the wire 0. Now thelever S carries besides the contact-point E a point P, which is locatedexactly opposite a similar point Q on the lever F. The action justreferred to, by which the movements of the diaphragm tend to prolong theexpansion of the wire 0, will accordingly tend also to prolong thecontact of the points P and Q when the latter is moved toward it by amovement of the diaphragm due to the effects of a sound-wave or to anyother cause that is to say, the apparatus here illustrated produceseffects similar to those produced by the construction illustrated inFig. 1, except that the automatic circuitbreaker is included in adistinct circuit from that which constitutes the primary circuit of thetelephone, the latter being made and broken by the approach andrecession of the levers, in the manner described. The contact of P and Qcloses the circuit of a battery R through the primary of aninduction-coil H, the secondary of which is connected with the telephoneT in a manner that is well understood in the art.

O is a condenser, and R a rheostat included in the circuit of battery R,to prevent sparking. Any other of the well-known devices for thatpurpose may be employed in its place.

The key A has connected with it an arm U, which, in the extremepositions of the key, rests against one or the other of twocontactpoints for connecting up with the line either the bell V or thetelephone T. This arrangement is also well understood and requires nospecial explanation.

The adjusting post or screw 0 is employed for regulating the tensionupon the wire 0. The lever F is cut and insulated at the point Y toguard against any interference between the batteries B and R in theiroperation.

v.A mouth-piece Z is employed to concentrate the sound-waves upon thediaphragm M.

I do not wish to confine myself to any'parlocated at a central stat-ion,or one battery may be arranged to serve for several transmitters. Thecontacts effected by the keyin Fig. 2 may be effected automatically by aself-acting switch. Again, the fine wire and contact-points may beplaced in series with the induction-coil, in which case the Wire must beattached to the lower diaphragrnin Fig.1 and its cooling producedbybreaking the circuit.

In Fig. 3 I have illustrated an arrangement for applying my invention toa carbon transmitter for the purpose of increasing its sensitiveness. Inthis construction I keep the carbon which is mounted on the diaphragm,in contact with a corresponding platinum contact-piece by means of afine wire under tension attached to the diaphragm. The circuit'in thisinstance,when the contact-points are together, is by way of wire 1,carbon button G, contact-point E, screw n, and metallic head n, wires 2and O, adjusting screw 0, wire 3, and primary of induction-coil. Thecontact expands the wire 0, thereby tending to break the circuit; butthe consequent coolin g of the wire contracts the same and closes thedescribed circuit. It will be observed that the frame J is cut andinsulation inserted at c for obvious reasons. lVith the constructionhere illustrated an equilibrium is set up between the elongation of thewire 0 and the resistance at the carbon contact, the result being thatthe pressure of the carbon is kept automatically at the most delicatepoint and a self-adjusting carbon transmitteris obtained. The changedthermostatic condition of the primary circuit is brought about in thisconstruction by a rupture of the circuit, due to the elongation of theresistance-wire,

or, rather, by an increase in the resistance of the circuit, and not,asin the other described forms, by the introduction of a shunt around theresistance-wire.

Fig. 4 illustrates an apparatus embodying the same principles as havealready been set forth, but in a slightly-different construction. Thecontact-point E is here cushioned against a soft-rubber cushion e, whichis of general spherical shape, and is provided with a perforationthrough which the wire C passes for attachment to the contact-piece."The wire also passes through a hollow screw j, which is set into thehead of the telephone. The ob- -je'ct of the cushion c is to render theapparatus more sensitive as regards the action of the wire 0 in responseto successive heating and cooling. The cushion forms a suiiicientlyrigid home for the contact E, and is at the same time sufficientlyyielding to respond quickly to the-expansion and contraction of O. Thediaphragm M is an insulating-diaphragm, preferably of wood.

In the invention set forth in the foregoing the fine wire C, with itsconnected contactpoint, forms an automatic circuit breaker whose makesand breaks produce no audible effects upon the circuit by reason of thegreat rapidity with which they follow each other that is to say, thenormal vibrations of the circuit-breaker considered with respect totheir capacity to reproduce sounds are nontral or inharmonious. Thatwhich reduces them to harmony and enables them to reproduce sounds insuitable receiving-instruments is the combinatiomwith the apparatuswhich produces them, of devices which bridge over or throw together moreor fewer of theinharmonious vibrations and thus alter their n atu ralsequence. By employing a thin diaphragm an d sealin g up all the worksin a heavy east-iron box to cutotl'outside vibrations, my apparatus mayeasily be made to serve as a telephonerepeater. The diaphragm shouldthen be arranged with an electro-magnet in proximity to it, the saidmagnet being included in the line over which impulses are being sent.

The diaphragm of my apparatus may be provided with a multiplicity ofcontacts connected either in series or in multiple arc.

Inthisspecifieationtheworddiaphragmis used to signify any device, ofwhatever shape, which may be caused to vibrate by impulses communicatedto it from any source. It is not necessary that both contacts should bemovable. For example, the contact G may be attached to a rigid support,and the proper effects may be produced for sending speech by talkingdirectly against the wire C or against a suitable covering or a shieldattached to the said wire.

Vhat I claim, therefore, is-

l. An automatic circuit breaker one of whose terminals is operativelyconnected with a diaphragm.

2. In a telephone-transmitter, a self-acting thermostatic circuitbreaker one of whose terminals is operativel y connected with adiaphragm.

3. In a telephone-transmitter, a self-acting thermostaticcircuit-breaker the expanding element of which is a conductor includedin the primary circuit of the telephone and actuated by the currenttherein, in combination with a diaphragm carrying one of the terminalsof the said circuit-breaker, and a short circuit connected to the saidterminal and also to the primary circuit beyond the said expandingelement.

4. The combination, with a diaphragm and a platinum contact-pointattached thereto, of a corresponding platinum contact-point forming partof a self-acting vibrator.

5. In a telephone-transmitter, a thermostatic circuit-breaker consistingof a line wire under tension in the primary circuit of the telephone,and a short circuit around the said wire, the said short circuit and thefine wire being attached to corresponding contact points, substantiallyas set forth.

6. In a telephone-transmitter, two contactpoints, one of which isoperatively connected with a diaphragm and the other with aresistance-wire under tension, in combination with a primarytelephone-circuit normally passing through the said wire, and a shortcircuit connected to the first-named contactpoint and also to the saidprimary circuit beyond the said resistance-wire, the tension of the saidwire upon the said second contactpoint being relieved by a spring orcushion, as and for the purpose set forth.

7. An automatic circuit-breaker, in combination with atelephonediaphragm and mouth-piece, one of the terminals of the saidcircuit-breaker being supported upon the said diaphragm.

8. In a telephone-transmitter, a self-acting thermostaticcircuit-breaker the expanding element of which is a conductor ofconsiderable resistance included in the primary circuit of the telephoneand actuated by the current therein, in combination with the diaphragmcarrying one of the terminals of the said circuit-breaker, and a shortcircuit connected to the said terminal and also to the primary circuitbeyond the said expanding element, the normal primary circuit includinga switch for disconnecting the said circuit at will.

9. In a telephone-transmittcr, a selfacting thermostatic circuit-breakerthe expanding element of which is a conductor included in the primarycircuit of the telephone and actuated by the current therein, incombination with a diaphragm carrying one of the terminals of the saidcircuit-breaker.

10. A self-adjusting thermostatic transmitter consisting of anexpansible conducting element forming part of the primary circuit of thetelephone, in combination with a diaphragm to which the expansibleelement is attached, and a pair of electrodes, one of which is connectedwith the diaphragm, whereby the strength of the current will determineby its heating eifect the degree of contact between the electrodes,substantially as described.

11. A self-adjusting thermostatic carbon transmitter consisting of anexpansible conducting element forming part of the primary circuit of thetelephone, in combination with a diaphragm to which the expansibleelement is attached, and a pair of electrodes, one of which is carbonand connected with the diaphragm, whereby the strength of the

